scholarly journals Parameters of temperature disturbance triggering the propagation of the quench front on an extremely overheated surface

2021 ◽  
Vol 2119 (1) ◽  
pp. 012079
Author(s):  
I P Starodubtseva ◽  
A N Pavlenko
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Front Propagation ◽  
Solid Contact ◽  
Temperature Disturbance ◽  
Metal Plates ◽  
Leidenfrost Temperature ◽  
Dynamical Pattern ◽  
Temperature Surface

Abstract The results of computational experiments simulating the triggering of the quench front propagation on the superheated vertically oriented metal plates are presented. The plates are quenched by a gravitationally flowing down liquid nitrogen film. The temperature of the test samples at the beginning of the process was higher than the critical temperature and the Leidenfrost temperature, which means that direct long-term liquid-solid contact is impossible. For this reason, the front is initially motionless. As a result of numerical simulation, a dynamic pattern of the quench front propagation on a high-temperature surface was obtained. Analysis of the results allowed to find the realistic values of heat sink into the cooling medium, as well as the parameters of the local temperature disturbance, its spatial extent and amplitude, at which the conditions are created for triggering the process of quench front propagation on the high-temperature surface. Direct comparison of the numerical simulations results with experimental data on the velocity, geometry of the quench front and on the dynamical pattern of the process confirmed the reliability of the results obtained.

scholarly journals Mechanism and Kinetics of Thermal Embrittlement of Austenitic Chromium-Nickel Steel during Long-Term High-Temperature Holding

2022 ◽  
Author(s):  
K.A. Okhapkin
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Structural Changes ◽  
Nickel Steel ◽  
Thermal Embrittlement ◽  
Calculation Results ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Equilibrium Content

Abstract. This article describes a model of structural changes in austenitic chromium-nickel steel during long-term thermal soakings. The time for reaching equilibrium content of Cr23C6 carbide at a temperature of 600 °C is calculated. The calculation results are compared with experimental data on the kinetics of thermal embrittlement of steel at a temperature of 600 °C after thermal holding for up to 15000 hours.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

Modelling of Moisture Movement in Wood during Outdoor Storage

2001 ◽  
Vol 6 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas ◽  
I. Juodeikienė ◽  
A. Kajalavičius
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Climatic Conditions ◽  
Two Dimensional ◽  
Moisture Movement ◽  
Finite Difference Technique ◽  
Long Term Storage ◽  
Space Formulation ◽  
Term Storage

A model of moisture movement in wood is presented in this paper in a two-dimensional-in-space formulation. The finite-difference technique has been used in order to obtain the solution of the problem. The model was applied to predict the moisture content in sawn boards from pine during long term storage under outdoor climatic conditions. The satisfactory agreement between the numerical solution and experimental data was obtained.

KUBOTA KNC-03

Alloy Digest ◽  
2010 ◽  
Vol 59 (1) ◽  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Temperature Performance ◽  
Resistance To Oxidation

Abstract Kubota KNC-03 is a grade with a combination of high strength and excellent resistance to oxidation. These properties make this alloy suitable for long-term service at temperature up to 1250 deg C (2282 deg F). This datasheet provides information on physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep. It also includes information on high temperature performance as well as casting and joining. Filing Code: Ni-676. Producer or source: Kubota Metal Corporation, Fahramet Division. See also Alloy Digest Ni-662, April 2008.

ATI 6-2-4-2

Alloy Digest ◽  
2020 ◽  
Vol 69 (8) ◽  
Keyword(s):  
Tensile Strength ◽  
Titanium Alloy ◽  
High Temperature ◽  
Creep Strength ◽  
High Strength ◽  
Heat Treating ◽  
Good Combination ◽  
Long Term Stability ◽  
Temperature Performance

Abstract ATI 6-2-4-2 is a near-alpha, high strength, titanium alloy that exhibits a good combination of tensile strength, creep strength, toughness, and long-term stability at temperatures up to 425 °C (800 °F). Silicon up to 0.1% frequently is added to improve the creep resistance of the alloy. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ti-169. Producer or Source: ATI.

Tribotechnical characteristics of hard alloys in sliding friction units

2020 ◽  
pp. 87-97
Author(s):  
K. D. Khromushkin ◽  
B. G. Ushakov ◽  
A. V. Kochergin ◽  
R. A. Suleev ◽  
O. N. Parmenova
Keyword(s):  
Experimental Data ◽  
Sliding Friction ◽  
Heating Temperature ◽  
Hard Alloys ◽  
Friction Units ◽  
Wear And Friction ◽  
Friction Path ◽  
Friction Parameters ◽  
Tribotechnical Characteristics ◽  
Temperature Surface

The paper presents experimental data on the study of the friction parameters of hard alloys in sliding friction units, including the heating temperature, surface roughness, wear and friction coefficient, depending on the duration of the test and the friction path.

scholarly journals CO Detection Investigation at High Temperature by SiC MISFET Metal/Oxide Gas Sensors

Proceedings ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 41
Author(s):  
Lida Khajavizadeh ◽  
Anita Lloyd Spetz ◽  
Mike Andersson
Keyword(s):  
High Temperature ◽  
Gas Sensors ◽  
Elevated Temperatures ◽  
Long Term Stability ◽  
Stability Performance ◽  
Catalytic Metal ◽  
Co Detection ◽  
Effect Transistor ◽  
Metal Oxide Gas Sensors

In order to investigate the necessary device improvements for high-temperature CO sensing with SiC metal insulator semiconductor field effect transistor (MISFET)-based chemical gas sensors, devices employing, as the gas-sensitive gate contact, a film of co-deposited Pt/Al2O3 instead of the commonly used catalytic metal-based contacts were fabricated and characterized for CO detection at elevated temperatures and different CO and O2 levels. It can be concluded that the sensing mechanism at elevated temperatures correlates with oxygen removal from the sensor surface rather than the surface CO coverage as observed at lower temperatures. The long-term stability performance was also shown to be improved compared to that of previously studied devices.

First Demonstration of High Temperature SiC CMOS Gate Driver in Bridge Leg for Hybrid Power Module Application

2018 ◽  
Vol 924 ◽  
pp. 854-857
Author(s):  
Ming Hung Weng ◽  
Muhammad I. Idris ◽  
S. Wright ◽  
David T. Clark ◽  
R.A.R. Young ◽  
...  
Keyword(s):  
High Temperature ◽  
Integrated Circuits ◽  
Initial Increase ◽  
Reliability Test ◽  
Power Devices ◽  
Power Module ◽  
Hybrid Power ◽  
Gate Driver ◽  
Passive Circuit

A high-temperature silicon carbide power module using CMOS gate drive technology and discrete power devices is presented. The power module was aged at 200V and 300 °C for 3,000 hours in a long-term reliability test. After the initial increase, the variation in the rise time of the module is 27% (49.63ns@1,000h compared to 63.1ns@3,000h), whilst the fall time increases by 54.3% (62.92ns@1,000h compared to 97.1ns@3,000h). The unique assembly enables the integrated circuits of CMOS logic with passive circuit elements capable of operation at temperatures of 300°C and beyond.

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